If you like live theater, experience a play at Theatre Antique. Look online to see what's still available.
This arts and culture attraction in Vienne is well-liked by travelers, so put it on your must-see list. Don't think the sightseeing ends there, however. There are a lot more places waiting for you to check out after Theatre Antique. Temple d'Auguste et de Livie, Gallo-Roman Museum of Saint-Romain-en-Gal, and Vienne Cathedral are close by.